Caulerpin (22) was able to inhibit both hypoxia (1% O2)- and chemical hypoxia (10 μM 1,10-phenanthroline)-induced HIF-1α activation with comparable potency, and while being unable to inhibit the induction of VEGF and GLUT-1 mRNAs by 1,10-phenanthroline in human breast cancer T47D cells, there was a marked decrease on the hypoxia-derived induction of both target genes [127]. This evidence concerns the gene HIF1A and breast cancer.